Esempio n. 1
0
/*
 * Walk curr->robust_list (very carefully, it's a userspace list!)
 * and mark any locks found there dead, and notify any waiters.
 *
 * We silently return on any sign of list-walking problem.
 */
void compat_exit_robust_list(struct task_struct *curr)
{
	struct compat_robust_list_head __user *head = curr->compat_robust_list;
	struct robust_list __user *entry, *pending;
	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
	compat_uptr_t uentry, upending;
	compat_long_t futex_offset;

	/*
	 * Fetch the list head (which was registered earlier, via
	 * sys_set_robust_list()):
	 */
	if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
		return;
	/*
	 * Fetch the relative futex offset:
	 */
	if (get_user(futex_offset, &head->futex_offset))
		return;
	/*
	 * Fetch any possibly pending lock-add first, and handle it
	 * if it exists:
	 */
	if (fetch_robust_entry(&upending, &pending,
			       &head->list_op_pending, &pip))
		return;
	if (upending)
		handle_futex_death((void *)pending + futex_offset, curr, pip);

	while (compat_ptr(uentry) != &head->list) {
		/*
		 * A pending lock might already be on the list, so
		 * dont process it twice:
		 */
		if (entry != pending)
			if (handle_futex_death((void *)entry + futex_offset,
						curr, pi))
				return;

		/*
		 * Fetch the next entry in the list:
		 */
		if (fetch_robust_entry(&uentry, &entry,
				       (compat_uptr_t *)&entry->next, &pi))
			return;
		/*
		 * Avoid excessively long or circular lists:
		 */
		if (!--limit)
			break;

		cond_resched();
	}
}
void compat_exit_robust_list(struct task_struct *curr)
{
	struct compat_robust_list_head __user *head = curr->compat_robust_list;
	struct robust_list __user *entry, *next_entry, *pending;
	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
	unsigned int uninitialized_var(next_pi);
	compat_uptr_t uentry, next_uentry, upending;
	compat_long_t futex_offset;
	int rc;

	if (!futex_cmpxchg_enabled)
		return;

	if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
		return;
	if (get_user(futex_offset, &head->futex_offset))
		return;
	if (fetch_robust_entry(&upending, &pending,
			       &head->list_op_pending, &pip))
		return;

	next_entry = NULL;	
	while (entry != (struct robust_list __user *) &head->list) {
		rc = fetch_robust_entry(&next_uentry, &next_entry,
			(compat_uptr_t __user *)&entry->next, &next_pi);
		if (entry != pending) {
			void __user *uaddr = futex_uaddr(entry, futex_offset);

			if (handle_futex_death(uaddr, curr, pi))
				return;
		}
		if (rc)
			return;
		uentry = next_uentry;
		entry = next_entry;
		pi = next_pi;
		if (!--limit)
			break;

		cond_resched();
	}
	if (pending) {
		void __user *uaddr = futex_uaddr(pending, futex_offset);

		handle_futex_death(uaddr, curr, pip);
	}
}
Esempio n. 3
0
/*
 * Walk curr->robust_list (very carefully, it's a userspace list!)
 * and mark any locks found there dead, and notify any waiters.
 *
 * We silently return on any sign of list-walking problem.
 */
void compat_exit_robust_list(struct task_struct *curr)
{
	struct compat_robust_list_head __user *head = curr->compat_robust_list;
	struct robust_list __user *entry, *next_entry, *pending;
	unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
	compat_uptr_t uentry, next_uentry, upending;
	compat_long_t futex_offset;
	int rc;

	if (!futex_cmpxchg_enabled)
		return;

	/*
	 * Fetch the list head (which was registered earlier, via
	 * sys_set_robust_list()):
	 */
	if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
		return;
	/*
	 * Fetch the relative futex offset:
	 */
	if (get_user(futex_offset, &head->futex_offset))
		return;
	/*
	 * Fetch any possibly pending lock-add first, and handle it
	 * if it exists:
	 */
	if (fetch_robust_entry(&upending, &pending,
			       &head->list_op_pending, &pip))
		return;

	next_entry = NULL;	/* avoid warning with gcc */
	while (entry != (struct robust_list __user *) &head->list) {
		/*
		 * Fetch the next entry in the list before calling
		 * handle_futex_death:
		 */
		rc = fetch_robust_entry(&next_uentry, &next_entry,
			(compat_uptr_t __user *)&entry->next, &next_pi);
		/*
		 * A pending lock might already be on the list, so
		 * dont process it twice:
		 */
		if (entry != pending) {
			void __user *uaddr = futex_uaddr(entry, futex_offset);

			if (handle_futex_death(uaddr, curr, pi))
				return;
		}
		if (rc)
			return;
		uentry = next_uentry;
		entry = next_entry;
		pi = next_pi;
		/*
		 * Avoid excessively long or circular lists:
		 */
		if (!--limit)
			break;

		cond_resched();
	}
	if (pending) {
		void __user *uaddr = futex_uaddr(pending, futex_offset);

		handle_futex_death(uaddr, curr, pip);
	}
}